Genetic diversity and population structure of Epichloë fungal pathogens of plants in natural ecosystems

Understanding the population genetic processes driving evolution of plant pathogens is central interest to pathologists and evolutionary biologists alike. However, most studies focus on host-pathogen associations in agricultural systems high environmental homogeneity less known about structure pathogen populations infecting wild plants natural ecosystems. We performed parallel sampling two pathogenic Epichloë species occurring sympatrically different host grasses seminatural grasslands Europe: E. typhina Dactylis glomerata clarkii Holcus lanatus . sequenced 422 haploid isolates generated genome-wide SNP datasets investigate diversity structure. In both geographically separated formed genetically distinct groups, however, separation was compared The patterns among admixture also differed between across same geographic range: we found higher levels differentiation a stronger effect isolation by distance , consistent with lower gene flow former. This pattern may be explained dispersal abilities expected influenced populations. addition, indicative effective size typhina. These results suggest that drift efficacy selection differ species. Our study provides evidence how ecologically similar occupying geographical space can experience contexts, which could influence local adaptation co-evolutionary dynamics these fungal pathogens.